Apparatus for parallel face finishing

ABSTRACT

1,069,174. Grinding. MICROMATIC HONE CORPORATION. Oct. 11, 1965 [Dec. 23,1 964], No. 42939/65. Heading B3D. Apparatus for finishing parallel faces of a workpiece rotatable about an axis perpendicular to the faces comprises: (a) a housing mounted for reciprocation in a plane perpendicular to the axis, the housing including at least one pair of parallel spaced longitudinally extending guide surfaces; (b) a pair of abrasive stones carried by the housing for movement therewith; and (c) means carried by the housing and movable along the guide surfaces for moving the stones into engagement with a workpiece face. The disc 14, Fig. 1, of a disc brake is supported between fixtures, one of which is rotatably supported by an adjustable hand wheel 16 and the other is carried by the shaft of an electric motor 18 serving to rotate the disc. Two opposing pairs of abrasive tool assemblies are mounted in a tool housing 23 vertically reciprocated on a fixed frame 13 by an hydraulic cylinder 15. Each tool assembly comprises an abrasive stone 33 fixed to a holder 35, Fig. 3 (not shown). Each holder has longitudinally spaced tapered rear faces 37 engaging tapered faces 39 on a plate 41 slidable in a groove in the tool housing. To advance the stone into contact with the workpiece, pressure fluid is admitted through inlet 51 and acts on a piston 43 to move the plate 41 downwards. To remove the plate 41 upwards, pressure fluid is admitted through inlet 63 and acts on a piston 55, the stone being retracted from the workpiece by leaf springs 65. In operation, the workpiece is mounted between the fixtures and the motor 18 actuated to rotate the workpiece. With the stones retracted the tool housing 23 is lowered. The stones are advanced into contact with the workpieces and the housing reciprocated rapidly to produce a random surface grain structure or slowly to produce a concentric surface grain structure. The operation may be terminated by a timer or by a gauging device. In a modification. Fig. 7 (not shown), the tool housing 23 is reciprocated through a connecting rod 75 by a crank-pin 77 on a disc 73 driven by a variable speed motor. The workpiece 14 is raised into finishing position by a lift 83 hydraulically or otherwise actuated, and having a concavity 85 to cradle the workpiece. One fixture 87 is reciprocable by a fluid motor 89 or a hand wheel and has a tapered end portion 91 engaging a central opening 93 in the workpiece to raise it clear of the lift and press it into engagement with the other fixture. The workpieces may be handled automatically.

ug- 1, 1967 A. s. czuBAK E'rAL 3,333,365

APPARATUS FOR PARALLEL FACE FINISHING Aug 1, 1967 A. s. czuBAK ETAL3,333,366

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United States Patent O 3,333,366 APPARATUS FUR PARALLEL FACE FINISHINGAlbin S. Czubak, Detroit, and Robert W. Militzer, Huntington Woods,Mich., assignors to Micromatic Hone Corporation, Detroit, Mich., acorporation of Michigan Filed Dec. 23, 1964, Ser. No. 420,751

7 Claims. (Cl. 51-67) This invention relates to abrading devices, andparticularly to an improved apparatus for finishing parallel faces ofparticular workpieces.

In machining work faces of some workpieces, it is important that thesesurfaces be finished fiat and to a high degree of parallelism. Anexample of this type workpiece is the disc of a disc brake assembly.Such a disc has a pair of outwardly facing parallel annular fiat faceswhich are engaged by brake pads. The fiatness and parallelism of thesefaces must be established to a high degree of accuracy in the finishingoperation; otherwise, uneven braking forces would be experienced in useand these faces would be subject to uneven wear and the useful life ofthe brake materially shortened. It is also important in finishing theparallel faces on rotatable workpieces like the above disc-type brakesthat the finished faces be accurately designed perpendicular to the'workpiece rotational axis. Otherwise, the brake shoes would be causedto wobble and apply uneven braking forces, reducing braking efiiciencyand subjecting the brake assembly to high fatigue stresses.

The present invention deals with apparatus adapted to finish work facesof this type to a high degree of accuracy. Brieiiy, the inventionincludes an improved abrading tool housing and tool guiding assembly ofrelatively simple but sturdy construction adapted to finish worksurfaces to a high degree of accuracy as to flatness and parallelism, aswell as to provide the work surfaces with a highly accurate surfacefinish, finish pattern and dimension control. A frame is provided whichrigidly supports the workpiece adjacent the tool housing and may beadapted to rotate the workpiece about its central axis. The abradingtool assembly is adapted to move transversely of the workpiecerotational axis whereupon abrasive tools provided thereon are displacedrelative to the tool assembly into contact with the parallel faces ofthe workpiece. Thus, by then rotating the workpiece about its centralaxis and engaging the work faces with abrasive tools, the parallel faceswill be accurately finished. In use, the tool assembly is reciprocatedat a controlled rate in a plane disposed perpendicular to the workpiecerotational axis while the workpiece undergoes rotation. In this way, thefinished work faces may be designed to possess a variety of surfacegrain contour. After the finishing operation is completed, the tools areretracted from the workpiece and the tool assembly withdrawn.

It is an object therefore of the present invention to provide animproved method and apparatus capable of establishing a high degree offiatness and parallelism on finished faces of a workpiece.

It is a further object of the present invention to provide an improvedapparatus of the above type wherein the finished faces of the workpieceare accurately dimensioned and perpendicular to a central axistherethrough and have an accurately controlled surface finish.

It is a further object of the present invention to provide an abradingtool assem-bly of the above type having an improved tool guidingassembly.

It is a further object of the present invention to provide an abradingtool assembly of the above type movable into and out of a work engagingposition as a unit.

It is a further object of the present invention to provide an abradingtool assembly of the above type adapted to ACC be reciprocated at acontrolled rate during the abrading operation.

It is a further object of the present invention to provide an abradingapparatus capable of providing a variety of surface finish patterns.

It is a further object of the present invention to provide an abradingtool assembly of .the above type which is relatively inexpensive tomanufacture, rugged in construction and reliable in operation.

Further objects and advantages of the present invention 'will becomemore apparent from the following detailed description taken inconjunction with the drawings in which:

FIGURE 1 is a perspective view of a honing machine embodying theprinciples of the present invention;

FIG. 2 is an enlarged fragmentary view of the structure of FIG. 1showing the abrading tool assembly of the present invention at the upperand lower reciprocatory limits of its abrading movement as illustratedby the full dotdash lines, respectively;

FIG. 3 is a sectional view of the structure of FIG. 2 taken along theline 3 3 thereof;

FfG. 4 is an end View of the structure of FIG. 2 taken in the directionof the arrow 4;

FIG. 5 is an enlarged view of a workpiece showing one type of surfacegrain structure attainable with the device of the present invention;

FIG. 6 is an enlarged view of a workpiece showing another type ofsurface grain structure attainable with the device of the presentinvention; and

FIG. 7 is a View similar to FIG. 1 showing a modified form of toolhousing drive.

Referring now more specifically to the drawings, FIG. l illustrates ahoning machine which is seen to include a base 11 to which an uprightframe 13 is suitably affixed. A fixture frame 12 is suitably supportedupon the base 11 and is adapted to support and position a workpieceduring the finishing operation. In the illustrated embodiment, aworkpiece consisting of a conventional disc-type automotive brake 14 issupported between suitable fixtures (not shown), one of which may berotatably supported by an adjustable hand wheel 16 and the other carriedby the output shaft (not shown) of an electric motor 1S. Both the hand'wheel and motor are supported upon the fixture frame 12 and thesefixtures are of a conventional type which will rigidly support theworkpiece for rotation and are readily xed thereto. Thus, rotation ofthe output shaft of motor 18 will, through the fixtures, impart rotationto the workpiece about its central axis.

A hydraulic cylinder 15 is suitably fixed Vto frame 13 and has disposedtherein a piston 17 for vertical movement relative thereto. A suitablesource of hydraulic fiuid may be supplied to the cylinder in the usualmanner by a means (not shown) to cause vertical reciprocation of thepiston. An adapter 19 may be formed integral with the lower end ofpiston 17 and is provided with a pair of flanges 21 at its lower end. Atool housing 23 is provided at its upper end with a pair of retainers 25each of which snugly receives a respective one of flanges 21. Thus, thetool housing will reciprocate vertically with piston 17.

Each rear side edge of the tool housing is formed with an elongatednotch 27, each of which slidably receives a guide rail 29 suitablycarried by and fixed to frame 13. Each of lthese guide rails is snuglybut slidably retained Iwithin its respective notch by a retainer plate31 suitably fixed to the rear of the tool housing. Thus, movement of thetool housing will be accurately controlled by the guide rails.

Disposed within the tool housing for movement therewith are a pluralityof abrasive tool assemblies each consisting of an abrasive stone 33fixed to a stone holder 35. While the number of these tool assembliesprovided may 35 vary by choice, for nishing the disc-type brakeillustrated, two opposing pairs of stones and stone holders are used.Each of the stone holders shown is provided with a plurality oflongitudinally spaced identical tapered faces 37 at its rear edgepositioned to engage complementary tapered faces 39 formed on each offour expander plates 41. As shown, these expander plates are closely butslidably retained each within a longitudinally extending groove 42formed in the tool housing by a plurality of retainer plates 44 suitablyfixed thereto. By carefully machining the longitudinal surfaces of theseexpander plates and grooves 42 in which they slide, and by maintaining aclose sliding relationship therebetween, the abrasive stones will bemaintained in accurate parallelism with themselves and each other whenmoved into contact with the workpiece and the work faces finishedaccordingly.

A plurality of primary pistons 43 are each positioned within acorresponding primary -cylinder 45 formed within the tool housing andare adapted for vertical -reciprocating movement relative thereto. Eachof the primary pistons is operatively connected to a respective one ofexpander plates 41 by suitable means such as a pin 47 to thereby impartcorresponding reciprocatory movement thereto and each of the pistons isprovided with a conventional O-ring 48 to sealingly engage the wall ofcylinders 45. An end cap 49 is suitably attached atop tool housing 23 toclose the ends of primary cylinders 45 and is provided with a pluralityof inlet openings 51 adapted to threadedly receive fluid conduits 53.Thus, as fluid is supplied under pressure to each conduit 53 in aconventional manner, downward movement will be imparted to pistons 43and therefore to expander plates 41. This will in turn cause movement ofeach of the tool assemblies inwardly toward the workpiece, by engagementbetween tapered faces 37 and 39 on the tool holders and expander plates,respectively, until the tools engage workpiece 14.

To retract the tool assemblies outwardly away from the workpiece at theconclusion of the finishing operation, a plurality of secondary pistonsS are provided and each has one end disposed for vertical movementwithin a plurality of secondary cylinders 57 formed in housing 23, whilethe other end of each of the secondary pistons abuts the lower end of .arespective one of the primary pistons. Each of pistons 55 carries aconventional O-ring 59 lwhich sealingly engages the wall of thecorresponding cylinder 57 while a plurality of fiuid conduits 6'1 aresuitably -connected to cylinders 57 at openings 63 to supply hydraulicfluid thereto. Thus, upon completion of the honing operation, thepressure on fluid to conduits 53 may be released and fluid underpressure may be supplied by conduits `61 to the secondary cylinders.This will move pistons 55, and therefore pistons 43, upwardly withtapered faces 39 on the expander plates moving away from faces 37 on thestone holders. A suitable means, such as leaf springs 65 fixed to thetool housing with one end of each engaging a respective end of eachstone holder 35, will then move each of the tool assemblies outwardlyaway from the workpiece.

As shown, the tool housing is movable from a position completely aboveand away from the workpiece (FIG. l), to a position where the workpieceis received within a longitudinal opening 67 formed therein (FIG. 3),and is adapted to be cycled reciprocally at a controlled rate through afinishing stroke illustrated by the full line and dot-dash positionsshown in FIG. 2 by controlling the rate of flow of fluid to -cylinder15. Also, the tool assemblies are movable from `a position retractedfrom the workpiece (not shown) to a position where stones 33 engage theworkpiece (FIG. 3) by :suitably controlling the fiow of fiuid tocylinders 45 and 57. While the details of these controls, including asuitable fluid source, pumps, and valves have not been illustrated, itis to be understood that the same will be of a conventional nature andwithin the realm of the skilled hydraulics engineer. The

fluid system provided will be controlled from suitable control panel 69mounted upon the machine fra-me.

In the operation of this m-achine, the workpiece is mounted between thefixtures carried by hand wheel assembly 16 and motor 18 and the motor isactuated to rotate the workpiece. With the tool assemblies in theirretracted positions, which can be accomplished by normally maintainingfluid under pressure to openings 63 of cylinders 57 and exhausting fluidfrom cylinders 45, fiuid is supplied to cylinder 15 to move piston 17downwardly. Thereafter, fluid is supplied to cylinders 45 by conduits 53:and is exhausted from cylinders 57 by conduits 61 thereby moving stones33 into engagement with workpiece 14. Depending upon the surface grainstructure desired on the workpiece, the tool housing will then bereciprocated at a fast rate of travel, through a preselected stroke, oneexample of which is indicated by the full line .and dot-dash positionsof FIG. 2, or the tool housing will reciprocate through this stroke at areduced rate of travel. In the former, a random type surface grainstructure or lay pattern, as illustrated by FIG. 6, will be formed onthe workpiece by the rapid rate of relative longitudinal movementbetween the stones and workpiece during the finishing operation. In thelatter, a concentric lay pattern, as illustrated in FIG. 5, is formedsince a reduced rate of relative longitudinal movement takes placebetween the stones and workpiece. Thus, the resulting surface grainstructure may be varied according to customer desires.

After completion of the abrading operation, which may be determined byeither a timer or by a suitable gauging device, fiuid is exhausted fromthe primary cylinders and is supplied to the secondary cylinders withsprings 65 retracting the tool assemblies, whereupon fiuid may besupplied to cylinder 15 to move piston 17 upwardly and the finishedworkpiece removed from the fixtures.

FIG. 7 illustrates a modified form of reciprocating -drive means for thetool housing and yworkpiece positioning means. This structure is, in allother respects, substantially identical to that of FIG. 1 and likenumerals indicate identical parts.

Thus, a drive motor (not shown) is fixed to the frame 13 and is providedwith a rotary output shaft 71 having a crank disc 73 fixed -theretoadjacent the end thereof. A connecting rod 75 is pivotally connected atone end to the disc 73 by a pin 77 and at its other end by a pin 81 to aspaced pair of ears 79 fixed to the tool housing 23. The pin 77 isdisposed eccentrically of the disc 73 so that rotation of ythe disc bythe drive motor (not shown) causes the tool housing to reciprocatevertically. As in the device of FIG. 1, the tool housing 23 is guided byguide rails 29 fixed to the frame 13.

The tool housing drive means of FIG. 7 is energized to reciprocate thetool housing 23 at a rapid rate when it is desired to form a random typesurface grain structure or lay pattern, as illustrated by FIG. 6 anddescribed above in the device of FIG. 1. Conversely, this tool housingdrive means reciprocates the -tool housing 23 at a relatively slow ratewhen it is desired to form a concentric lay pattern shown in FIG. 5 andalso described above. This variable rate of tool housing reciprocationis achieved by using a variable speed -drive motor to drive the crank73.

In the device of FIG. l, the tool assembly was moved adjacent andretracted from the workpiece 14 by supplying fluid to the cylinder 15 tomove the piston 17. In the device of FIG. 7, the workpiece 14 is raisedinto position in preparation for the finishing operation by a movablelift -83 which is hydraulically or otherwise suitably actuated. Asshown, the lift 83 is formed concave as a-t 85 to cradle the workpiece14 and is moved upwardly to raise the workpiece 14 to a positionadjacent the rotatable fixtures one of which is shown .at 87. Thefixture I87 is reciprocable, as by a fluid motor 89 or by a hand wheelas shown in FIG. 1, and is extended to grip the workpiece 14. For

handling the disc brake 1'4 shown, the fixture 87 has `a tapered endportion 91 positionable within an opening 93 centrally of the workpiece14 to raise it slightly from the lift 83 and press it into engagementwith the other fixture (not shown) whereupon the motor 18 which drivesthe fixtures is energized. Thereafter, the tool assemblies are movedinto engagement with the workpiece 14 and the finishing process iscarried out as described above. Upon completion of the finishingprocess, the tool assemblies are retracted and the lift `83 lowered. Thefinished workpiece is removed and a new workpiece 14 is placed on thelift cradle surface 85 in preparation for the next finishing process.

The lift device 83 can :be motivated by any suitable drive means such asa fluid motor. In addition, the work pieces 14 can be manually placed onand removed from the cradle surf-ace `85 or they can be handledautomatically as desired. In addition, suitable guide means may beprovided to prevent the workpiece 14 from falling off the lift 83 duringits raising and lowering sequence.

Thus, by the present invention there has Ibeen provided an abrading`device for finishing parallel faces on a workpiece which will form flatfinished faces accurately parallel to each other and perpendicular tothe workpiece axis of rotation.

While preferred embodiments of -the present invention have beenillustrated and described in detail, various additions, substitutions,modifications and omissions may be made thereto without departing fromthe spirit of the invention as encompassed by the appended claims.

What is claimed is: 1. In a device for finishing parallel faces of aworkpiece rotatable about an axis perpendicular to said faces,

a housing mounted for reciprocation in a plane perpendicular to the axisof rotation of said workpiece,

said housing having two pairs of parallel spaced longitudinallyextending guide rail surfaces formed thereon, one of each of said pairsadjacent a respective one of said work faces,

a plurality of abrasive stones carried by said housing,

one each adjacent a respective one of said rail surfaces for movementtherewith,

and means carried by said housing and movable in unison along said railsurfaces for moving said stones into engagement with a respective one ofsaid workpiece faces.

2. In a device for finishing parallel faces of a workpiece rotatableabout an axis perpendicular to said faces,

a frame,

a housing mounted for reciprocation in a plane perpendicular to therotational aXis of said workpiece and guided by said frame,

means defining two pairs of parallel spaced elongated guide railsurfaces formed on said housing and extending in the direction ofreciprocation thereof,

an abrasive stone supported adjacent each of said guide rail surfaces,

and means carried by said housing and movable relative thereto alongsaid guide rail surfaces for moving said stones into contact with saidworkpiece faces.

3. In a device for finishing parallel faces of a workpiece rotatableabout an axis perpendicular to said faces,

a frame,

a housing mounted for reciprocation in a plane perpendicular to therotational axis of said workpiece and guided by said frame,

means defining two pairs of parallel spaced elongated guide railsurfaces formed on said housing and extending in the direction ofreciprocation thereof,

an abrasive tool assembly supported adjacent each of said guide railsurfaces and each having at least one cam surface formed thereon,

cam means carried by said housing and movable relative thereto alongsaid guide rail surfaces,

and a cam surface formed on e-ach said cam means and engageable with thecam surface on a respective one of said tool assemblies whereby saidstones are moved into contact with said workpiece faces upon movement ofsaid cam means along said guide rail surfaces.

4. In a device for finishing parallel faces of a workpiece rotatableabout an axis perpendicular to said faces,

a frame,

-a housing mounted for reciprocation in a plane perpendicular to therotational laxis of said workpiece and guided by said frame,

A means defining two pairs of parallel spaced elongated guide railsurfaces formed on said housing and ex tending in the direction ofreciprocation thereof,

an abrasive tool assembly supported adjacent each of said guide railsurfaces and each having at least one cam surface formed thereon,

means biasing each said tool assembly toward its respective guide frailsurface,

cam means carried by said housing and movable relative thereto alongsaid 4guide rail surfaces,

and a cam surface formed on each said cam means and engageable with thecam surface on a respective one of said tool assemblies whereby saidstones are moved against said biasing means and into contact with saidworkpiece faces upon movement of said cam means along said guide lrailsurfaces.

S. In a device for finishing parallel faces of -a workpiece rotatableabout an axis perpendicular to said faces,

a frame,

a housing guidably mounted on said frame for reciprocation along a planeperpendicular to the rotational axis of said workpiece,

said housing bein-g formed with at least one pairof spaced parallelelongated guide rail surfaces extending in the direction ofreciprocation thereof,

an abrasive tool positioned adjacent each said guide rail surface,

resilient means normally biasing each said tool toward its respectiveguide rail surface,

cams means carried by said housing `and movable relative thereto alongeach said guide rail surface from a first position spaced from saidabrasive tools to a second position in engagement with a respective oneof said abrasive tools to thereby move said tools into engagement with arespective one of said work faces,

and means for controllably reciprocating said housing during engagementbetween said abrasive tools and said workpiece.

6. In a device for finishing parallel faces of a workpiece rotatableabout an axis perpendicular to said faces,

a frame,

a housing guidably mounted on said frame for reciprocation along a planeperpendicular .to the rotational axis of said workpiece,

said housing being formed with lat least one pair of spaced parallelelongated guide rail surfaces extending in the direction ofreciprocation thereof,

an abrasive tool positioned adjacent each said guide rail surface,

resilient -means normally biasing each said tool toward its respectiveguide rail surface,

elongate means supported by said housing one each movable along arespective one of said guide rail surfaces,

each said elongate means being formed with a plurality of longitudinallyspaced tapered cam surfaces engageable with complementary surfacesformed on each said abrasive tool,

means for moving each said elongate means from a first position wheresaid cam surfaces are spaced from said complementary surfaces to asecond position where said cam surfaces engage said complementarysurfaces to thereby move each said abrasive tool into engagement with arespective one of said work faces,

and means for reciprocating said housing during engagement rbetween saidabrasive tools and said workpiece.

7. In a device for finishing parallel faces of a workpiece rotatableabout an -axis perpendicular to said faces,

a frame,

a hous-ing guidably mounted on said frame for reciprocation along aplane perpendicular to the rotational aXis of said workpiece,

said housing being formed with at least one pair of spaced parallelelongated guide rail surfaces extending in the direction ofreciprocation of said housing,

an abrasive tool positioned adjacent each said lguide rail surface,

resilient means normally biasing each said tool toward its respective`guide rail surface,

elongate means supported by said housing one each movable along arespective one of said guide rail surfaces,

each said elongate means being formed with a plurality of longitudinallyspaced tapered cam surfaces engageable with complementary surfacesformed on each said abrasive tool,

uid pressure actuated means for moving each said elongate means from afirst position Where said cam surfaces are spaced from saidcomplementary surfaces to a second position where said cam surfacesengage said complementary surfaces to thereby move each said abrasivetool into engagement with a respective one of said work faces,

and means for reciprocating said housing during engagement between saidabrasive tools and said workpiece.

References Cited UNITED STATES PATENTS 2,127,071 8/1938 Schmalz 51-562,195,065 3/194() Wallace 51-60 2,315,859 4/1943 Indge 51-67 2,703,4703/1955 Porter 51-67 X HAROLD D. WHITEHEAD, Primary Examiner.

1. IN A DEVICE FOR FINISHING PARALLEL FACES OF A WORKPIECE ROTATABLEABOUT AN AXIS PERPENDICULAR TO SAID FACES, A HOUSING MOUNTED FORRECIPROCATION IN A PLANE PERPENDICULAR TO THE AXIS OF ROTATION OF SAIDWORKPIECE, SAID HOUSING HAVING TWO PAIRS OF PARALLEL SPACEDLONGITUDINALLY EXTENDING GUIDE RAIL SURFACES FORMED THEREON, ONE OF EACHOF SAID PAIRS ADJACENT A RESPECTIVE ONE OF SAID WORK FACES, A PLURALITYOF ABRASIVE STONES CARRIED BY SAID HOUSING, ONE EACH ADJACENT ARESPECTIVE ONE OF SAID RAIL SURFACES FOR MOVEMENT THEREWITH, AND MEANSCARRIED BY SAID HOUSING AND MOVABLE IN UNISION ALONG SAID RAIL SURFACESFOR MOVING SAID STONES INTO ENGAGEMENT WITH A RESPECTIVE ONE OF SAIDWORKPIECE FACES.